1. Technical Field
The techniques described herein relate to wireless power transfer, and in particular to a wireless power transfer apparatus that can wirelessly transfer power to a mobile device and a wearable device, and to a wireless power transfer apparatus that can wirelessly transfer power to an electronic device within a cavity.
2. Discussion of the Related Art
Wireless Power Transfer Systems (WPTS) are gaining increasing popularity as a convenient way to deliver power without wires or connectors. WPTS currently under development in the industry can be separated in two major classes: magnetic induction (MI) systems and magnetic resonance (MR) systems. Both types of systems include a wireless power transmitter and a wireless power receiver. Such systems can be used to power or charge mobile devices such as smartphones or tablet computers, among other applications.
Inductive WPTS typically operate in an allocated frequency range of several hundred kilohertz using frequency variation as a power flow control mechanism. MR WPTS typically operate on a single resonant frequency using input voltage regulation to regulate output power. In typical applications, MR WPTS operate at a frequency of 6.78 MHz.
Several industry committees such as the Wireless Power Consortium (WPC), the Power Matters Alliance (PMA), and the Alliance for Wireless Power (A4WP) have been working on developing international standards for consumer products based on wireless power transfer.
WPTS have been developed that can charge multiple mobile devices at the same time. Such devices include a charging pad that can accommodate multiple mobile devices on the surface of the charging pad.